The Spotted Flounder, Azygopus Flemingi Nielsen 1961 (Pisces: Pleuronectiformes Rhombosoleidae), from Deep Waters Off New Zealan

The spotted flounder, Azygopus flemingi Nielsen 1961 (Pisces: Pleuronectiformes: Rhombosoleidae), from deep waters off New Zealand: a second valid species of Azygopus Norman 1926, with notes on distribution, size, maturity, and ecology

THOMAS A. MUNROE 1 1National Systematics Laboratory, NMFS/NOAA, Smithsonian Institution, Post Office Box 37012, NHB, WC 57, MRC–153, Washing- ton, DC 20013–7012,U.S.A. Email: [email protected]

Abstract

Since its description, Azyygopus Norman, 1926 was considered by subsequent authors to be a monotypic genus in the Or- der Pleuronectiformes comprised only of A. pinnifasciatus Norman, 1926, known from deep waters (90–900 m, usually 200–600 m) off the southern and southeastern coasts of Australia. In 1961, a subspecies, A. pinnifasciatus flemingi Niels- en, was described based on three specimens collected at 610 m in the Tasman Sea off the South Island, New Zealand. From its description to contemporary literature evaluating its status, recognition of A. p. flemingi as a distinct taxon has been rejected by all but two studies reporting on Azygopus from New Zealand waters. Until the late 20th century, specimens of Azygopus had been rarely collected off New Zealand and little was known about these fishes. Over the past 25 years, col- lecting by scientific expeditions and expanding deep-sea fisheries have captured over 195 specimens of Azygopus from a variety of deep-sea locations around New Zealand. Recently-captured specimens of Azygopus collected around New Zea- land and deposited in fish collections have been identified as either A. pinnifasciatus Norman or A. flemingi Nielsen, sug- gesting the possibility that two species of Azygopus occur in New Zealand waters. This study examined the holotype, a paratype, and 25 non-type specimens of A. pinnifasciatus collected off Australia, and the most comprehensive series of specimens of Azygopus collected from New Zealand waters. These specimens included the holotype and two paratypes of A. p. flemingi and 191 other specimens collected from throughout the entire depth range (153–942 m) and representing wide coverage of geographic areas around New Zealand where Azygopus have been collected. Comparisons of these specimens indicate that a second species, A. flemingi Nielsen, should be recognized in the genus Azygopus, and that this species is the only member of this genus occurring in New Zealand waters. Azygopus flemingi is readily distinguished from A. pinnifasciatus by conspicuous differences in ocular- and blind-side color patterns, in numbers of ocular-side pelvic-fin rays, total vertebrae, lateral-line scales, and gillrakers on the first gill arch, morphology of blind-side scales and squamation patterns, length of blind-side pectoral fins, presence/absence of scales between upper jaw and ventral margin of lower eye, and pigment patterns on dorsal and anal fins of adults. Adult A. flemingi and A. pinnifasciatus are sexually dimorphic in several features. Data on maximum size and size at maturity, and depth of occurrence are summarized for A. flemingi.

Key words: rhombosoleid flatfish; taxonomy; New Zealand endemic fishes; deep-sea flatfish; species re-description; squamation; scale morphology; Azygopus pinnifasciatus; sexual dimorphism

Introduction

Azyygopus Norman, 1926 has been considered by most subsequent authors (Norman 1934; Sakamoto 1984; Evseenko 2004; Gomon 2008; Eschmeyer & Fricke 2012) to be a monotypic genus in the Order Pleuronectiformes comprising only A. pinnifasciatus Norman, 1926. Azygopus pinnifasciatus had been reported only from deep-water locations (90–900 m, usually 200–600 m) off the southern and southeastern coasts of Australia (Norman, 1926; Norman 1934) until Moreland’s (1957) report of deepwater flatfishes, identified as A. pinnifasciatus, taken in 1954 off the Chatham Islands, New Zealand. Though Moreland’s report (based on an unknown number of specimens) represents the first published record for specimens of Azygopus from New Zealand waters, these were not the first representatives of this genus collected from this region.

Accepted by M.T. Craig: 1 Mar. 2012; published: 2 May 2012 1